The present invention relates generally to a system and method for displaying flight mode annunciators, and more particularly, to flight mode annunciators incorporated into the primary flight display (PFD) for improving a pilot""s situational awareness.
A pilot""s awareness and coordination of various aircraft modes and conditions is often critical to optimum aircraft performance and safety. For example, the pilot should be aware of the aircraft""s automation state and the pilot should be able to easily coordinate the flight director modes. Moreover, the pilot should be able to easily view and coordinate the tracking of the aircraft to current modes and targets. However, existing cockpit controls, which may be of the panel mounted variety or of the head up display (HUD) variety and which may be commonly found in commercial, military, and civilian aircraft, include various systems distributed throughout the cockpit, thereby often requiring the pilot to intermittently scan various areas of the cockpit to obtain and analyze the aircraft information. As such, pilots may fly certain modes in an inappropriate manner.
To assist the pilot, aircraft flight displays continue to advance in sophistication, achieving increasingly higher levels of information density and, consequently, presenting a greater amount of visual information to be perceived and understood by the operator. In many applications, it is often important that visual displays provide a proper cognitive mapping between what the operator is trying to achieve and the information available to accomplish the task. As a result, such systems increasingly utilize human-factor design principles in order to build instrumentation and controls that work cooperatively with human operators. Accordingly, the Federal Aviation Administration (FM) has promulgated a number of standards and advisory circulars relating to flight instrumentation. More particularly, Title 14 of the U.S. Code of Federal Regulations, Federal Aviation Regulations (FAR) Part 25, Sec. 25.1321 et seq. provides guidelines for arrangement and visibility of instruments, warning lights, annunciators, and the like. Similarly, detailed guidelines related to electronic displays can be found in FAA Advisory Circular 20-88A, Guidelines on the Marking of Aircraft Powerplant Instruments (Sept. 1985), both of which are incorporated by reference.
An exemplary primary flight display (PFD) 5 generally includes an Attitude Direction Indicator (ADI) 10, a heading source indicator (HSI) 25, a Flight Modes Area (FMA) 30 and other critical annunciators, such as, for example, altitude selection (ASEL) 50, current altitude 55 and vertical speed 60 (see FIG. 1). An ADI typically indicates a reference point or line, e.g., a representative horizon line, relative to the position of the host aircraft. The host aircraft may be represented by a fixed element of the ADI 10 display and most ADIs depict the aircraft wings as one or more horizontal marks that are centered with respect to the display screen. The horizon line rendered on the ADI 10 display may move up and down in response to changes in the pitch of the aircraft. Similarly, the horizon line may rotate in response to changes in the roll of the aircraft. More particularly, ADI 10 includes an indicator for the flight director 15 and the aircraft 20, wherein the flight director 15 conforms to the modes set by the pilot and provides guidance based upon the pre-selected modes. Using the ADI, the pilot can appropriately manipulate the aircraft relative to the flight director 15. If the autopilot is engaged, the aircraft automatically follows the flight director 15. Without the autopilot, the pilot receives guidance, but the pilot manually directs the aircraft in the direction of the flight director 15.
Many conventional ADIs include a blue colored portion above the horizon line (representing the sky) and a brown or tan colored portion below the horizon line (representing the Earth). This color scheme is employed to enable pilots to determine the attitude of the aircraft at any given moment. The color scheme is particularly helpful in situations where the pilot may be temporarily distracted or in situations where visibility is impaired. While an ADI having such a color scheme may be suitable in many situations, a pilot may have difficulty detecting small changes in tilt and roll based on slight movement of the horizon line and/or slight movement of the blue and brown colored segments.
ADIs and other related instrumentation may display alphanumeric or graphical information related to the direction of the aircraft relative to a specific reference point such as the horizon. However, the manner in which such information is typically displayed requires the pilot to scan the instrumentation panel (or HUD field), locate the displayed information, and interpret the information. Depending upon the current flight conditions, it may be difficult for a pilot to quickly and easily locate and digest such information. Consequently, the reaction time associated with adjusting the direction of the aircraft toward the reference point may be undesirably long.
The FMA 30 is typically located in the upper portion of the PFD 5 because this area is in the pilot""s primary scanning view. As such, in a typical aircraft, an area is normally reserved in the upper portion of PFD 5 for important annunciators, such as, for example, an upper row of active annunciators, including the status of the engagement of the autopilot functions, and a lower row indicating if the modes are currently armed. Additionally, the lateral modes are indicated on the left side of FMA 30, while the vertical modes are indicated on the right side of the FMA 30. Moreover, the modes of the aircraft are often indicated on PFD 5 by 3-5 letter acronyms, such as, for example, LNAV (lateral navigation) is an active lateral mode, AP (autopilot) for the autopilot engage status and FPA (flight path angle) is an active vertical mode.
Although critical information is located within the PFD 5, important information related to the aircraft""s state, modes and targets is typically missing from PFD 5, wherein the additional information and annunciators regarding the aircraft would substantially assist a pilot""s awareness of aircraft conditions. For example, if the approach has been programmed, but the pilot has not yet armed an approach, the pilot needs sufficient time to allow for normal capture of the approach such that the pilot can select the approach (APR) pushbutton to arm the system for the approach. However, many of the fault analysis systems are not located within the PFD 5; and instead, are located in another area of the cockpit which often requires the pilot to remove PFD 5 from his/her line of vision and scan over to another area of the cockpit displays. In particular, the Crew Alerting System (CAS) includes only certain fault annunciations, so the pilot only scans over to the CAS to analyze if the certain faults may exist. As such, systems and methods are needed to overcome these and other limitations of the prior art. Specifically, there is a long felt need for flight mode annunciators incorporated into the PFD which improve a pilot""s situational awareness.
The pilot""s awareness of the aircraft""s state is enhanced by supplementing the flight modes area (FMA) in the upper region of the primary flight display (PFD) with additional annunciators. The FMA in the present invention displays, in the active lateral modes region, the name of the waypoint the aircraft is flying towards and, if the waypoint is part of a published procedure, the procedure name is displayed in this area. Moreover, if the controls of the aircraft are set for a specific target, then the target, along with the mode annunciators, are displayed in the active vertical modes region of the FMA. Furthermore, if the aircraft starts to deviate from the preselected altitude, the pilot is alerted of the uncoordinated condition by a CHECK ASEL annunciation which is displayed in the lower center region of the FMA, namely below the autopilot (AP) annunciator. Additionally, if the approach has been programmed, but the pilot has not yet armed an approach, the crew is alerted to the condition by an annunciation which is displayed in the lower center region of the FMA in sufficient time to allow for normal capture of the approach such that the pilot can select the approach (APR) pushbutton to arm the system for the approach. If more than one annunciator is to be displayed in a location, the most critical annunciator is consistently or intermittently displayed until the critical situation is resolved.